Updated Results from the SLAC ESTB T-506 Irradiation Study 2014 - - PowerPoint PPT Presentation

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Updated Results from the SLAC ESTB T-506 Irradiation Study 2014 - - PowerPoint PPT Presentation

Feb 03, 2024 27 likes •289 views

Updated Results from the SLAC ESTB T-506 Irradiation Study 2014 Linear Collider Workshop Belgrade, Serbia 6-10 October 2014 Bruce Schumm UC Santa Cruz Institute for Particle Physics On behalf of the FCAL Collaboration T-506 Motivation

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Updated Results from the SLAC ESTB T-506 Irradiation Study

2014 Linear Collider Workshop Belgrade, Serbia 6-10 October 2014

Bruce Schumm UC Santa Cruz Institute for Particle Physics

On behalf of the FCAL Collaboration

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T-506 Motivation

BeamCal maximum dose ~100 MRad/yr BeamCal is sizable: ~2 m2 of sensors. A number of ongoing studies with novel sensers: GaAs, CVD diamond  Are these radiation tolerant?  Also, might mainstream Si sensors be of use? Some reasons for optimism for Si…

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Departure from NIEL (non-ionizing energy-loss) scaling

  • bserved for electron irradiation

NIEL e- Energy 2x10-2 0.5 MeV 5x10-2 2 MeV 1x10-1 10 MeV 2x10-1 200 MeV G.P. Summers et al., IEEE Trans Nucl Sci 40, 1372 (1993)

Also: for ~50 MRad illumination of 900 MeV electrons, little loss of charge collection seen for wide variety of sensors [S. Dittongo et al., NIM A 530, 110 (2004)] But what about the hadronic component of EM shower?

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Hadronic Processes in EM Showers

There seem to be three main processes for generating hadrons in EM showers (all induced by photons):

  • Nuclear (“giant dipole”) resonances

Resonance at 10-20 MeV (~Ecritical)

  • Photoproduction

Threshold seems to be about 200 MeV

  • Nuclear Compton scattering

Threshold at about 10 MeV;  resonance at 340 MeV  These are largely isotropic; must have most of hadronic component develop near sample

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Irradiating the Sensors

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LCLS and ESA

Use pulsed magnets in the beam switchyard to send beam in ESA.

Mauro Pivi SLAC, ESTB 2011 Workshop, Page 6

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ESTB parameters

0.25 nC

Parameters ESA Energy 15 GeV Repetition Rate 5 Hz Charge per pulse 0.35 nC Energy spread, sE /E 0.02% Bunch length rms 100 mm Emittance rms (gex,gey) (4, 1) 10-6 m-rad Spot size at waist (sx,y) < 10 mm Drift Space available for experimental apparatus 60 m Transverse space available for experimental apparatus 5 x 5 m

3.5-10.5 (for now) Up to 10 Hz! ≤ 0.15 nC

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8

1 inch

Sensor

Pitch adapter, bonds

Daughter Board Assembly

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2 X0 pre-radiator; introduces a little divergence in shower Not shown: 4 X0 and 8 X0 radiators just before and after sensor Sensor sample

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Detector Fluence Distribution (per incident e-)

Radius (cm) Fluence (particles per cm2)

For later charge collection measurement, must have ~1cm2 uniformly illuminated area Raster sensor across beam

1.0 2.0 3.0

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Dose Rates (Including 1 cm2 Rastering)

Mean fluence per incident e-

Maximum dose rate (10.6 GeV; 10 Hz; 150 pC per pulse): 28 Mrad per hour

Confirmed with RADFET to within 10%

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T506 Si Doses

“P” = p-type “N” = n-type “F” = float zone “C” = Czochralski

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T506 GaAs Doses

New this year: GaAs pad sensors via Georgy Shelkov, JINR Dubna Irradiated with 5.7 and 21.0 Mrad doses of electromagnetically-induced showers Irradiation temperature 3oC; samples held and measured at -15oC

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Assessing the Radiation Damage

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Daughter/Readout Board Assembly

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Sensor + FE ASIC DAQ FPGA with Ethernet

Charge Collection Apparatus

  • Readout: 300 ns
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Channel-over- threshold profile Efficiency vs. threshold

Median Collected Charge

Charge Collection Measurement

2.3 MeV e- through sensor into scintillator

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Results

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Results: PF sensors

Doses of 5 and 20 Mrad No annealing

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Results: PC sensors

Dose of 20 Mrad No annealing

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Results: NF sensor for low dose

Doses of 5 and 20 Mrad No annealing

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Results: NF Sensor to 90 Mrad, Plus Annealing Study

Limited beneficial annealing to 90oC (reverse annealing above 100oC?)

Dose of 90 Mrad

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Results: NC sensors

Dose of 220 Mrad Incidental annealing ~15% charge loss at 300 ns shaping

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GaAs Charge Collection after 5.7 Mrad Exposure

15-20% charge loss at 300 ns shaping

GaAs Dose of 5.7 Mrad No annealing

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Compare to Direct Electron Radiation Results (no EM Shower)

Roughly consistent with direct result

kGy

Georgy Shelkov, JINR 1000 kGy = 100 Mrad

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Summary and Conclusions

  • In midst of a program of study of radiation

damage in a realistic EM shower environment

  • Have irradiated and studied several Si sensors

to as much as 220 Mrad, and GaAs to 6 Mrad.

  • Si sensors show some promise to survive the

BeamCal integrated dose

  • GaAs shows charge loss at 6 Mrad, but still

need to do annealing studies

  • Will soon explore 21 Mrad GaAs sensor and do

annealing studies on both GaAs sensors

  • Expect to run at higher fluence in 2015